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Add shadow frame link stack for trace recorder.

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Simplifies snapshots. Prerequisite for pre-call snapshots.
Increases consistency for fast function calls, too.
This commit is contained in:
Mike Pall
2010-02-04 03:08:29 +01:00
parent 78f5e2ffd3
commit 7256690364
6 changed files with 82 additions and 56 deletions
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53
src/lj_snap.c
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@@ -68,49 +68,26 @@ static MSize snapshot_slots(jit_State *J, SnapEntry *map, BCReg nslots)
return n;
}
/* Add frame links at the end of the snapshot. */
static MSize snapshot_framelinks(jit_State *J, SnapEntry *map)
{
cTValue *frame = J->L->base - 1;
cTValue *lim = J->L->base - J->baseslot;
MSize f = 0;
map[f++] = SNAP_MKPC(J->pc); /* The current PC is always the first entry. */
while (frame > lim) { /* Backwards traversal of all frames above base. */
if (frame_islua(frame)) {
map[f++] = SNAP_MKPC(frame_pc(frame));
frame = frame_prevl(frame);
} else if (frame_ispcall(frame)) {
map[f++] = SNAP_MKFTSZ(frame_ftsz(frame));
frame = frame_prevd(frame);
} else if (frame_iscont(frame)) {
map[f++] = SNAP_MKFTSZ(frame_ftsz(frame));
map[f++] = SNAP_MKPC(frame_contpc(frame));
frame = frame_prevd(frame);
} else {
lua_assert(0);
}
}
return f;
}
/* Take a snapshot of the current stack. */
static void snapshot_stack(jit_State *J, SnapShot *snap, MSize nsnapmap)
{
BCReg nslots = J->baseslot + J->maxslot;
MSize nent, nframelinks;
MSize nent;
SnapEntry *p;
/* Conservative estimate. Continuation frames need 2 slots. */
lj_snap_grow_map(J, nsnapmap + nslots + (MSize)J->framedepth*2+1);
/* Conservative estimate. */
lj_snap_grow_map(J, nsnapmap + nslots + (MSize)J->framedepth+1);
p = &J->cur.snapmap[nsnapmap];
nent = snapshot_slots(J, p, nslots);
nframelinks = snapshot_framelinks(J, p + nent);
J->cur.nsnapmap = (uint16_t)(nsnapmap + nent + nframelinks);
snap->mapofs = (uint16_t)nsnapmap;
snap->ref = (IRRef1)J->cur.nins;
snap->nent = (uint8_t)nent;
snap->nframelinks = (uint8_t)nframelinks;
snap->depth = (uint8_t)J->framedepth;
snap->nslots = (uint8_t)nslots;
snap->count = 0;
J->cur.nsnapmap = (uint16_t)(nsnapmap + nent + 1 + J->framedepth);
/* Add frame links at the end of the snapshot. */
p[nent] = SNAP_MKPC(J->pc); /* The current PC is always the first entry. */
memcpy(&p[nent+1], J->frame, sizeof(SnapEntry)*(size_t)J->framedepth);
}
/* Add or merge a snapshot. */
@@ -141,14 +118,14 @@ void lj_snap_shrink(jit_State *J)
lua_assert(nslots < snap->nslots);
snap->nslots = (uint8_t)nslots;
if (nent > 0 && snap_slot(map[nent-1]) >= nslots) {
MSize s, delta, nframelinks = snap->nframelinks;
MSize s, delta, depth = snap->depth;
for (nent--; nent > 0 && snap_slot(map[nent-1]) >= nslots; nent--)
;
delta = snap->nent - nent;
snap->nent = (uint8_t)nent;
J->cur.nsnapmap = (uint16_t)(snap->mapofs + nent + nframelinks);
J->cur.nsnapmap = (uint16_t)(snap->mapofs + nent + 1 + depth);
map += nent;
for (s = 0; s < nframelinks; s++) /* Move frame links down. */
for (s = 0; s <= depth; s++) /* Move PC + frame links down. */
map[s] = map[s+delta];
}
}
@@ -210,7 +187,7 @@ void lj_snap_restore(jit_State *J, void *exptr)
SnapShot *snap = &T->snap[snapno];
MSize n, nent = snap->nent;
SnapEntry *map = &T->snapmap[snap->mapofs];
SnapEntry *flinks = map + nent + snap->nframelinks;
SnapEntry *flinks = map + nent;
int32_t ftsz0;
BCReg nslots = snap->nslots;
TValue *frame;
@@ -224,6 +201,7 @@ void lj_snap_restore(jit_State *J, void *exptr)
}
/* Fill stack slots with data from the registers and spill slots. */
J->pc = snap_pc(*flinks++);
frame = L->base-1;
ftsz0 = frame_ftsz(frame); /* Preserve link to previous frame in slot #0. */
for (n = 0; n < nent; n++) {
@@ -236,7 +214,7 @@ void lj_snap_restore(jit_State *J, void *exptr)
lj_ir_kvalue(L, o, ir);
if ((sn & (SNAP_CONT|SNAP_FRAME))) {
/* Overwrite tag with frame link. */
o->fr.tp.ftsz = s != 0 ? (int32_t)*--flinks : ftsz0;
o->fr.tp.ftsz = s != 0 ? (int32_t)*flinks++ : ftsz0;
if ((sn & SNAP_FRAME)) {
GCfunc *fn = ir_kfunc(ir);
if (isluafunc(fn)) {
@@ -291,8 +269,7 @@ void lj_snap_restore(jit_State *J, void *exptr)
}
}
L->top = curr_topL(L);
J->pc = snap_pc(*--flinks);
lua_assert(map + nent == flinks);
lua_assert(map + nent + 1 + snap->depth == flinks);
}
#undef IR